This invention is directed generally to well data monitoring and control systems for acquiring downhole well data such as pressure, temperature, fluid flow rate, etc. of the fluid that is located within a well and for controlling various downhole well operations, particularly operations concerned with production of fluid from the well and displaying such data or otherwise controlling the well in response to such data. More particularly, this invention concerns the provision of a mandrel(s) or tubing carried well tool holder run into a well on a tubing string and which is provided with a plurality of internal, bottom entry, instrument or tool side pockets which are electrically inter-connected for power/control purposes to thus enable electronic well data sensors, instrument electric power equipment, well controller instruments and the like to be installed and retrieved, such as by use of a wireline running tool run inside the tubing while the tubing string and mandrel remain undisturbed within the well. This invention also concerns bottom entry, multiple pocket, tubing installed, mandrel(s) that can be adapted for housing instruments for controlling gas-lift valves or the like and other artificial lift devises such as submersible pumps and which instrument can also be installed and retrieved by wireline operations.
Each of the possibly multiple side pockets of such mandrel(s) are equipped with electrical connection means enabling circuit completion upon installation of an instrument or other electronic interconnection of apparatus located within the various pockets of the mandrel(s). The present invention is also directed generally to electrically operable gas-lift valves which can be operated from surface located controls via an electric wireline extending from the surface to the downhole gas-lift valve mandrel(s) or which alternatively can be operated by a programmed on-board electronic controller and power system. The present invention is further directed to the acquisition of well data such as pressure, temperature, fluid flow, etc. and also such monitoring and acquisition equipment incorporating a remotely operable valve for changing valve positioning for gas-lift operations and a downhole controller processor that can be programmed or reprogrammed according to the production capability of the well.
When wells are drilled and completed for the production of petroleum products the hydrocarbon bearing subsurface formations being encountered, unless the formation has been produced by other wells, typically has sufficient formation pressure via natural gas pressure in the formation fluid to produce fluid from the well by forcing it from the subsurface zone to the well bore and thence upwardly from the formation depth to the surface through a production tubing string that is suspended within the well casing. After the well has been produced for a period of time, determined by the character, volume and other parameters of the subsurface oil bearing formation, the natural gas pressure or drive will diminish to the point that efficient hydrocarbon production will cease. To continue well production, other artificial lift production systems, such as pumps, gas-lift systems, waterflood systems and the like can be employed. When the decision is made to change the well completion for different well fluid production parameters, it is typically necessary to bring a work-over rig to the well site, pull the production tubing string from the well and replace it with a production tubing string of the character desired, i.e. pump, gas-lift, etc. Considerable well down time, work-over costs end equipment costs are routinely required for well work-over of this nature. It is desirable therefore to minimize the expense of a work-over rig and its personnel for converting wells from formation pressure induced oil production to production by gas-lift or other artificial lifting means.
It is known in the gas-lift oil production art to provide a production tubing string having a plurality of spaced gas-lift mandrels with a gas lift valve pocket in each of the mandrels. To temporarily isolate the interior of the valve pockets from casing annulus pressure and from the fluid that may be present therein, dummy valve elements may be inserted into the valve pockets to seal and protect the interior polished seal sections of the pocket and thereby to isolate the production tubing from the casing annulus pressure that is present at the gas inlet port of the valve pocket. One of the problems with the use of such dummy valves is that retrieval of a dummy valve by a retrieval tool leaves the valve pocket open and in unchecked fluid communication with the production tubing until such later time as a gas-lift valve is subsequently run through the tubing string and installed within the pocket. This unchecked fluid communication can result in sufficient gas pressure change or pressure drop to stop flow or kill the well so that other expensive and time consuming operations are required to restore the well to active production. It is desirable therefore to provide a well control system that can produce a well efficiently by means of natural formation pressure and which can be efficiently controlled in the downhole environment to produce the well by gas-lift or other artificial lift operations without risking potential killing of the well or damaging its productive capacity during the conversion process.
When a well is in reservoir pressure production or gas-lift production it is often desirable to acquire downhole well fluid parameter measurements on a reasonably continuous basis so that the well and others wells producing the formation can be produced in a manner that enhances the long term production of the formation. By monitoring production tubing pressure and/or casing annulus pressure at various well depths and by providing for a wide range of fluid flow or fluid production control, the production system for the well can be efficiently tuned for the precise flow parameters that achieve maximum long term production from the well and the field. For this reason and others, various types of downhole data sensors and recorders have been developed which are positionable within the sensor pocket of a downhole mandrel and are powered by a surface-to-sensor circuit as shown by U.S. Pat. No. 4,624,309 of Schnatzmeyer. Such sensors may also be monitored by an on-board, self contained programmable data recorder as shown in U.S. Pat. No. 5,130,705 of Allen et al. A retrievable electronic well data recorder is also shown by U.S. Pat. No. 5,327,971 of Garbutt et al.
Mechanically or electrically operated gas-lift valves that are variable in the downhole environment have generally not been available. For the most part, prior art gas-lift valves have only two positions, open or closed, whether they are mechanically or electrically operated. Adjustment of lift gas injection by electrically operated on/off valves has been achieved by controlling electrically operated valves from the surface, such adjustment being accomplished by adjusting the time sequence of valve operation. In the case of pressure responsive mechanical gas-lift valves, the rate of gas injection flow into the production tubing from the casing/tubing annulus of the valves is typically governed by the orifice dimension of each valve. To change the rate of gas flow it is typically necessary to retrieve the valve and adjust its flow rate by manually changing the orifice size. If the valve is of the pressure operated or responsive type, it is also necessary to change the charging pressure of the internal pressure chamber. It is desirable therefore, to provide an electrically operated gas-lift valve having a wide range of adjustable gas injection flow capability by orifice opening control and also having adjustable valve timing, both being adjustable in the downhole environment by programmable processor or from the surface via a surface control unit via wireline.
Electrically operated gas-lift valves have also been developed for controlling the injection of gas into a tubing string for well fluid production as shown by U.S. Pat. No. 2,658,460. Electrically operated gas-lift valves have been of rotary or poppet type, with both being solenoid energized and with the rotary type having a mechanism for converting the linear motion of a solenoid to achieve rotary motion of the valve element. In either case, the valves have been of the on/off type (i.e. fully open or closed) with the rate of gas injection form the well annulus being controlled only by timing the xe2x80x9conxe2x80x9d (open) and xe2x80x9coffxe2x80x9d (closed) time cycles from a surface located controller, via an electric cable and by adjusting the timing sequence for valve operation. Electrically operated gas-lift valves having adjustable flow controlling orifices have more recently been developed, as shown by U.S. Pat. No. 5,176,164 of Boyle.
It is a principal feature of the present invention to provide a novel electrically operated system which is installed within the valve pocket of a gas-lift mandrel(s) having an electrical wet connection or an inductive coupler and which combines the features of an electrically operated gas-lift valve and a downhole well parameter monitor and data recorder in a single retrievable unit.
It is another feature of the present invention to provide a novel electrically operated system which may be installed within the valve pocket of a gas-lift mandrel having an electrical wet connection or an inductive coupler and which is operable either by an electrical power and control circuit extending to a surface located console or control computer, or by a downhole, battery powered, self contained, programmable and re-programmable processor.
It is an even further feature of the present invention to provide a novel electrically operated system which is installed within the valve pocket of a gas-lift mandrel(s) having an electrical wet connection or inductive coupler and which may be selectively retrieved for valve servicing or for downloading acquired well data to a surface computer for processing and subsequent well control use.
It is also a further feature of the present invention to provide an electrically operated retrievable unit having the on-board capability of acquiring downhole well data such as pressure, temperature, fluid flow, fluid viscosity, etc. and also incorporating an electrically operated valve for controlling valve orifice opening and flow rate for gas-lift operations and which can be operated by an electronic data processor/data memory system that can be programmed and reprogrammed according to the production capability of the well.
It is an even further feature of the present invention to provide a novel electrically operated system which may be installed within the valve pocket of a side pocket gas-lift mandrel(s) having an internal wet-connect type electrical connection or an inductive coupler and which provides the capability for sensing and recording downhole well data such as pressure, temperature, fluid flow, fluid viscosity, etc. and also incorporates an electrical mechanism for controlling valve orifice opening for well production control on gas-lift production operations and which is controlled by an electronic operation/data memory system that can be programmed or reprogrammed according to the production capability of the well.
Briefly, the various objects and features of the present invention are realized by the provision of a combination well flow control and well data acquisition system.
The system is run in the well on a production tubing string incorporating at least one or a plurality of longitudinally spaced side-pocket type mandrel(s) having internal side pockets electrically possibly and fluid pressure interconnected. A plurality of elongated retrievable electronic control and data acquisition instrument is provided. The control and data acquisition instruments are sized and adapted to fit within the respective internal pocket of the mandrel(s) and to be run on wireline inside production tubing using a kick over tool. The electronic circuits of the instruments have one or more wet-connect type electrical connectors or inductive type couplers for electrical wireline connection to the instruments. The instruments are provided with data sensing, transmittal and recording circuitry for acquiring various pressure and flow data. The system may also incorporate a remotely operable variable orifice valve mechanism for controlling entry of pressured gas from the casing/tubing annulus into the production tubing for lifting well fluid from the standing level within the well to the surface via the production tubing string. The variable orifice valve mechanism may be controlled via surface operated power and control circuitry, via wireline, or by battery powered on-board programmable and reprogrammable control circuitry for controlling injection of lift gas into the tubing string in accordance with the production capability of the well.